Philadelphia District Attorney Seth Williams pauses as he speaks during a news conference in Philadelphia, Friday, Feb. 10, 2017. Williams has announced he won't run for a third term amid an FBI probe into gifts he initially failed to report. (AP Photo/Matt Rourke)

PHILADELPHIA (AP) — Seth Williams, the city’s first black district attorney, won’t run for a third term amid an FBI investigation into $160,000 in gifts that he failed to report, mistakes that he said Friday caused his office “much embarrassment and shame.”

The Democrat later reported taking a new roof, a $2,700 couch and luxury vacations, including the use of a defense lawyer’s home in the Florida Keys. Williams has agreed to pay $62,000 in related ethics fines.

He did not take questions at a morning appearance in which he apologized for “mistakes in my personal life and in my personal financial life that cast an unnecessary shadow over my office.”

Williams, 50, intends to stay in the $175,000-a-year job through January. He previously served as the city’s inspector general, overseeing investigations into corruption within the city government. In college, he was the student body president at Penn State University.

At least four challengers had already jumped into the Democratic primary race, including a judge and a civil rights lawyer. The party has a stranglehold on citywide offices, so the primaries typically decide elections.

Williams has said he encountered financial problems amid a divorce and private school tuition costs for his children. He failed to disclose five sources of income and 89 gifts on 2010-2015 financial statements and omitted 10 items on an amended statement. The gifts also included sideline passes for Philadelphia Eagles games for several years, nearly $21,000 in free airfare and a $6,500 Rolex watch from a girlfriend.

At the same time, he led a high-profile prosecution of Philadelphia lawmakers who had taken cash or jewelry, valued at perhaps a few thousand dollars, from an informant.

“My poor judgment caused distractions, and made the already difficult job of my … staff even more difficult,” Williams said.

During his seven-year tenure, his office filed the first charges against several Roman Catholic priests and earned a trial conviction against the first U.S. church official ever charged over the handling of priest sex-abuse complaints. The conviction has since been overturned, although the official served nearly three years in prison.

His office has also worked to decriminalize low-level drug cases and, in keeping with a Supreme Court ruling, review 300 mandatory life sentences being served by juvenile offenders.

Federal agents subpoenaed records from Williams’ political action committee in 2015 but haven’t charged anyone. A lawyer representing Williams did not immediately return a call for comment Friday.

State laws require public officials to file annual reports and list gifts over $250. City officials cannot take anything worth more than $99 from anyone with an interest in any “official action.” Federal bribery laws typically involve a “quid pro quo,” or evidence the person got something in exchange for the gift.

Lawyer Richard Hoy, who owns the Key West house, had said he never got any special consideration for Williams’ use of the five-bedroom home.